In the domain of freight transport via airplanes, loading the interior of aircraft fuselages with products having varying degrees of rigidity and/or density is current practice. These products are most often installed in or on a rigid structure such as a container or a palette before being attached to the floor of the aircraft. The rigidity and/or density of these containers or palettes results in stresses, to a greater or lesser degree, on the structure of the aircraft and more particularly on the floor on which these containers or palettes are resting.
During flight, the aircraft is subject to different aerodynamic constraints which tend to move the floor of the aircraft elastically. For example, when the aircraft is in flight, the floor located around the trunk of the fuselage supporting the wing tends to flex to follow flexion in the wing box under the vertical load. Hence, as is shown in FIGS. 1 and 2 for the prior art, the distribution of loads on the floor of the aircraft varies depending on whether the aircraft is on the ground or in flight.
FIG. 1 shows a section of an aircraft at the wing box 2 of said aircraft, the aircraft being on the ground; FIG. 2 shows the same section of the aircraft when the aircraft is in flight.
The fuselage 1 is traversed in its lower part by the wing box 2. A floor 3 supports a rigid container 4. Generally speaking, in the subsequent description, a container means a crate, a palette, or any other rigid transport element that may be attached to the floor of an aircraft.
The container 4 rests along its entire lower surface 7 on the floor 3 such that the entire floor 3 produces work.
Conversely, when the aircraft is in flight, as is shown in FIG. 2 for the prior art, the distribution of loads is modified. In effect, the central wing box 2 is deformed due to the aerodynamic stresses undergone by the wing 8 which results in elastic movement in the floor attached to said central wing box 2.
The container 4 is then only supported by the lateral parts 5 and 6 of the floor 3 on which it is attached and which are themselves attached to the latter walls of the fuselage 1. The stresses are then no longer uniformly distributed to the entire surface of the floor 3 which initially supported the container 4, but are concentrated in the lateral parts 5 and 6 of the floor 3 where the container 4 is attached to the floor 3.
In the prior art, to alleviate this elastic movement in the floor 3 which tends to concentrate the stresses to the lateral areas 5, 6 of said floor 4, the floor 3 is reinforced with materials around the areas of the floor which are stressed during flight. This addition of materials contributes to a significant and permanent increase in the total mass of the aircraft, even though the problem of the poor distribution of the load on the floor structure of the aircraft is encountered only when transporting containers that are rigid and/or dense, and which are not capable of elastic movement to follow the elastic movement of the structure of the floor during flight. Even though the problem is encountered only occasionally, the mass of the aircraft is affected permanently by the addition of material forming the lateral reinforcements.